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Re: which is best for JOIN approach
Posted by: Ra Nala
Date: February 19, 2016 05:28AM

Rick James

i have applied your approach in my extraction queries and facing so many performance issues. i am not able to retrieve just 500000 records using below approach and it is your approach.

select ...
from inform a
left join (
SELECT ... FROM infmrq b JOIN contact ec on b.id=ec.id) on b.id=a.id
) AS bec ON

and

YOU have mentioned my case is different one that's why i am going to apply LEFT JOINS to all my tables why because i need all data from left table(i.e. first table) and want records from right side table if matched if they haven't matched will get null values.

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